An INDB file contains a book created by Adobe InDesign, a professional page layout and publishing program. It stores multiple .INDD documents, which comprise the pages and chapters of the book. INDB files also include the page numbers, indexes, and other formatting information.

INDB files are used for compiling documents into a larger book, as well as publishing and printing the final copy. They are often helpful for saving computer resources while editing, since the computer does not have to load all of the INDD file contents while creating the book. To create an INDB file, select File → New → Book..., name your book, choose your save location, and click Save. NOTE: Books can be accessed using the Book panel within InDesign. Books are separate from documents (INDD files), since one or more documents are used for populating the contents of the book.